Process of treating viscose.



D. E. REID.

PROCESS OF TREATING VISCOSE.

APPLICATION FILED PEB.21, 1914.

1,1 17,604. Patented Nov. 17, 1914.

* ED STATES PATENT oEEIcE.

' DAVID E. REID, OF ROCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COMPANY,

OF ROCHESTER, NEW YORK,

A CORPORATION OF NEW YORK.

PROCESS OF TREATING VISCOSE.

Specification of Letters Patent.

Patented Nov. 17, 1914.

Application filed February 21, 1914. Serial No. 820,148.

To all whom. it m'a concern:

Be it known t at I, DAVID E. REID, of Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Processes of Treating Viscose; and I do hereby declare the following to be a full, clear, and exact description of the same, reference be ing had to the accompanying drawings, forming a part of this specification, and to the reference-numerals marked thereon.

My present invention relates to the treat- I ment of viscose or cellulose xanthate and its formation into sheets, webs or filaments, and it has for its object to provide an improved process whereby such material maybe made continuous lengths and uniformly smooth, clear and transparent so that it is well adapted for use for any purpose and particularly as a support for sensitized emulsion and the manufacture of photographic film. The Process involves generally the treatment 0 an aqueous solution of viscose with a saturated solution of an alkaline sulfite, preferably of sodium sulfite, removing the sulfite from the material and rende g the viscose insoluble by the use of suitable agents such, for instance, as mineral acids, and finally, removing the acid by washing or neutralizing it. More specifically and in order to obtain the best results, in carrying out the process, I form the aqueous solution of viscose into its ultimate shape as a sheet, film or filament and reimlnarily coagulate or set its surface be ore it enters the li uid coagulant, so that its form or shape Wlll not be alteredby the latter, as, for instance, if sheeLis to be formed the viscose solution is depositedupon the surface of a carrier such as a drum, partially submer ed in the liquid and between the point 0% its application to the drum surface and the liquid coagulant it is subjected to the action of heat which will tend to slightly or more baths containing gradually ecreasing amounts of sulfite, then through a bath of a liquid which prepares the sheet for the a tank containing that a continuous circulation of freshsatuliquid rendering the sheet insoluble. In pract ce, after passing through two tanks containing the saturated solution, the sheet or Web passes through a tank containing a half saturated solution of sodium sulfite; then through a tank containing a 1'5 per cent. solution of sodium sulfite; then through a 20 per cent. solution of ammomum sulfate, then through a tank contaming a 5 per cent. solution of hydrochloric Or other suitable mineral acid; then through a tank containing an acid neutralizing mater1al such as a 2% per cent. solution of hypochlor1te of sodium, and afterward is washed n pure water. The strength of the solutions 1n the first tvo tanks is maintained by pumplng their contents into a reservoir con- .taimng an excess of sulfite and from said reservoir back through a suitable filter so rated solution is maintained and the sulfur compounds extracted by the first baths are removed, thus obviating any liability of unduly staining the viscose during the first coagulation. By the employment of sulfite solutions of gradually decreasing strength, the sulfur compounds are removed from the viscose and at the same time a, gradual, complete coagulation is obtained, thus materially strengthening the web and the farther the web travels, the cleaner it becomes, the treatment in each succeeding tank leaving less sulfite in it, and the ammonium sulfate then removes from the web the last remnant of/the sulfite and prepares it for the acid bath which renders the web insoluble. The acid is then neutralized by the solution of hypo-chlorite of sodium which also bleaches out any color remaining in it and the web is then washed in any suitable manner. When using the other alkaline sulfites, such as potassium, ammonium and lithium, the precipitation of the viscose is considerably slower.

The apparatus employed may be of any usual type, and in the drawings, I have shown a'conventional sectional view of a suitable machine consisting of a drum 1 partially submerged in the saturated solution of sulfite contained in the tank 3. Mounted above the drum is a suitable distributing hopper 4 for applying the li uid viscose to the surface, and 5 indicates a eater consisting of a hollow metallic chamber into which steam is applied, arranged in proximity to i the surface of the drum between the hopper and the surface of the liquid in the tank. 6 indicatesa tank containing saturated solution; 7 the tank containing the half saturated solution; 8 the tank-containing the 15 per cent. sulfite solution; 9]

the tank containing the ammonium sulfate solution; 10 the tank containing the acid solution; 11 the tank containing the chlorite of sodium solution, and 12 and 13 the Washing tanks. Each of these tanks also contains the upper and lower sets of rollers 14: and 15, respectively, around Whichthe Web passes and the rollers tween the tanks.

I claim as my invention:

1. The process of coagulating viscose, consisting in subjecting an aqueous solution thereof to the action of a saturated solution of sodium sulfite, removin the sulfite and rendering the material inso uble.

2. The process of coagulating viscose, consisting in subjecting an aqueous solution thereof to the action of a saturated solution of sodium sulfite and then to one or more baths containing a lesser percentage of so dium sulfite, then removin' the sulfite and rendering the material inso uble.

8. The process of coagulating viscose, consisting in subjecting an aqueous solution thereof to the action of sodium sulfite, then to the action of ammonium sulfate, then to an acid, and then removing the acid.

the second hypo-.,

16 arranged be- I the sulfite, then' rendering the material nuance 4:. The process of coagulating viscose, consisting in subjecting an aqueous solution thereof to the action of a saturated solution of sodium sulfite, then to. several separate baths containing gradually decreasing uperand then tion of sodium su fite.

7. The process of coagulating viscose, con-.

sisting in subecting an aqueous solution to the action 0 a saturated solution of alkaline sulfite, rendering the material insoluble.

8. The process of coagulating viscose, consisting in subjecting an aqueous solution thereof to the action of a saturated solution of an alkaline sulfite and then to one or more baths containing a lesser percentage of removing the sulfite and insoluble. j DAVID E. REID. Witnesses:

C. E. Mariam,

Anmann A. Mansion.

an. removing the sulfite and setting the surface H 

